{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*",
            "extracted_events": [
              {
                "introduced": "9.20.0"
              },
              {
                "fixed": "9.20.21"
              },
              {
                "introduced": "9.21.0"
              },
              {
                "fixed": "9.21.20"
              }
            ],
            "source": "CPE_RANGE"
          },
          "events": [
            {
              "introduced": "14bbdfc7b9db0870a0b8941ca8812d9983fdba1a"
            },
            {
              "fixed": "12f97d4162d435940598de4870d0088b8e6d266c"
            },
            {
              "introduced": "b732da695eecc0526950e2c722cde0bf23e5a070"
            },
            {
              "fixed": "3e7037ceef40688d5b4eb4a55a9df80c7547dd9f"
            }
          ],
          "repo": "https://github.com/isc-projects/bind9",
          "type": "GIT"
        }
      ]
    },
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*",
            "extracted_events": [
              {
                "introduced": "9.20.0"
              },
              {
                "fixed": "9.20.21"
              },
              {
                "introduced": "9.21.0"
              },
              {
                "fixed": "9.21.20"
              }
            ],
            "source": "CPE_RANGE"
          },
          "events": [
            {
              "introduced": "14bbdfc7b9db0870a0b8941ca8812d9983fdba1a"
            },
            {
              "fixed": "12f97d4162d435940598de4870d0088b8e6d266c"
            },
            {
              "introduced": "b732da695eecc0526950e2c722cde0bf23e5a070"
            },
            {
              "fixed": "3e7037ceef40688d5b4eb4a55a9df80c7547dd9f"
            }
          ],
          "repo": "https://gitlab.isc.org/isc-projects/bind9",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {},
  "details": "A use-after-return vulnerability exists in the `named` server when handling DNS queries signed with SIG(0). Using a specially-crafted DNS request, an attacker may be able to cause an ACL to improperly (mis)match an IP address. In a default-allow ACL (denying only specific IP addresses), this may lead to unauthorized access. Default-deny ACLs should fail-secure.\nThis issue affects BIND 9 versions 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, and 9.20.9-S1 through 9.20.20-S1.\nBIND 9 versions 9.18.0 through 9.18.46 and 9.18.11-S1 through 9.18.46-S1 are NOT affected.",
  "id": "CVE-2026-3591",
  "modified": "2026-07-08T05:38:36.302410863Z",
  "published": "2026-03-25T14:16:37.297Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://kb.isc.org/docs/cve-2026-3591"
    },
    {
      "type": "FIX",
      "url": "https://downloads.isc.org/isc/bind9/9.20.21"
    },
    {
      "type": "FIX",
      "url": "https://downloads.isc.org/isc/bind9/9.21.20"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}